s390/kvm: remove explicit -EFAULT return code checking on guest access
Let's change to the paradigm that every return code from guest memory
access functions that is not zero translates to -EFAULT and do not
explictly compare.
Explictly comparing the return value with -EFAULT has already shown to
be a bit fragile. In addition this is closer to the handling of
copy_to/from_user functions, which imho is in general a good idea.
Also shorten the return code handling in interrupt.c a bit.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 37116a7..5afa931 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -180,7 +180,7 @@
struct kvm_s390_interrupt_info *inti)
{
const unsigned short table[] = { 2, 4, 4, 6 };
- int rc, exception = 0;
+ int rc = 0;
switch (inti->type) {
case KVM_S390_INT_EMERGENCY:
@@ -188,74 +188,38 @@
vcpu->stat.deliver_emergency_signal++;
trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
inti->emerg.code, 0);
- rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1201);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, inti->emerg.code);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
- &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- __LC_EXT_NEW_PSW, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
+ rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1201);
+ rc |= put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, inti->emerg.code);
+ rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ __LC_EXT_NEW_PSW, sizeof(psw_t));
break;
-
case KVM_S390_INT_EXTERNAL_CALL:
VCPU_EVENT(vcpu, 4, "%s", "interrupt: sigp ext call");
vcpu->stat.deliver_external_call++;
trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
inti->extcall.code, 0);
- rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1202);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, inti->extcall.code);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
- &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- __LC_EXT_NEW_PSW, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
+ rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1202);
+ rc |= put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, inti->extcall.code);
+ rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ __LC_EXT_NEW_PSW, sizeof(psw_t));
break;
-
case KVM_S390_INT_SERVICE:
VCPU_EVENT(vcpu, 4, "interrupt: sclp parm:%x",
inti->ext.ext_params);
vcpu->stat.deliver_service_signal++;
trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
inti->ext.ext_params, 0);
- rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2401);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
- &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- __LC_EXT_NEW_PSW, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);
- if (rc == -EFAULT)
- exception = 1;
+ rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2401);
+ rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ __LC_EXT_NEW_PSW, sizeof(psw_t));
+ rc |= put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);
break;
-
case KVM_S390_INT_VIRTIO:
VCPU_EVENT(vcpu, 4, "interrupt: virtio parm:%x,parm64:%llx",
inti->ext.ext_params, inti->ext.ext_params2);
@@ -263,34 +227,16 @@
trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
inti->ext.ext_params,
inti->ext.ext_params2);
- rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2603);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, 0x0d00);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
- &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- __LC_EXT_NEW_PSW, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u64(vcpu, __LC_EXT_PARAMS2,
- inti->ext.ext_params2);
- if (rc == -EFAULT)
- exception = 1;
+ rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2603);
+ rc |= put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, 0x0d00);
+ rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ __LC_EXT_NEW_PSW, sizeof(psw_t));
+ rc |= put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);
+ rc |= put_guest_u64(vcpu, __LC_EXT_PARAMS2,
+ inti->ext.ext_params2);
break;
-
case KVM_S390_SIGP_STOP:
VCPU_EVENT(vcpu, 4, "%s", "interrupt: cpu stop");
vcpu->stat.deliver_stop_signal++;
@@ -313,18 +259,14 @@
vcpu->stat.deliver_restart_signal++;
trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
0, 0);
- rc = copy_to_guest(vcpu, offsetof(struct _lowcore,
- restart_old_psw), &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- offsetof(struct _lowcore, restart_psw), sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
+ rc = copy_to_guest(vcpu,
+ offsetof(struct _lowcore, restart_old_psw),
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ offsetof(struct _lowcore, restart_psw),
+ sizeof(psw_t));
atomic_clear_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
break;
-
case KVM_S390_PROGRAM_INT:
VCPU_EVENT(vcpu, 4, "interrupt: pgm check code:%x, ilc:%x",
inti->pgm.code,
@@ -332,24 +274,13 @@
vcpu->stat.deliver_program_int++;
trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
inti->pgm.code, 0);
- rc = put_guest_u16(vcpu, __LC_PGM_INT_CODE, inti->pgm.code);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u16(vcpu, __LC_PGM_ILC,
- table[vcpu->arch.sie_block->ipa >> 14]);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_to_guest(vcpu, __LC_PGM_OLD_PSW,
- &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- __LC_PGM_NEW_PSW, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
+ rc = put_guest_u16(vcpu, __LC_PGM_INT_CODE, inti->pgm.code);
+ rc |= put_guest_u16(vcpu, __LC_PGM_ILC,
+ table[vcpu->arch.sie_block->ipa >> 14]);
+ rc |= copy_to_guest(vcpu, __LC_PGM_OLD_PSW,
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ __LC_PGM_NEW_PSW, sizeof(psw_t));
break;
case KVM_S390_MCHK:
@@ -358,24 +289,13 @@
trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
inti->mchk.cr14,
inti->mchk.mcic);
- rc = kvm_s390_vcpu_store_status(vcpu,
- KVM_S390_STORE_STATUS_PREFIXED);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u64(vcpu, __LC_MCCK_CODE, inti->mchk.mcic);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_to_guest(vcpu, __LC_MCK_OLD_PSW,
- &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- __LC_MCK_NEW_PSW, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
+ rc = kvm_s390_vcpu_store_status(vcpu,
+ KVM_S390_STORE_STATUS_PREFIXED);
+ rc |= put_guest_u64(vcpu, __LC_MCCK_CODE, inti->mchk.mcic);
+ rc |= copy_to_guest(vcpu, __LC_MCK_OLD_PSW,
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ __LC_MCK_NEW_PSW, sizeof(psw_t));
break;
case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
@@ -388,67 +308,44 @@
vcpu->stat.deliver_io_int++;
trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
param0, param1);
- rc = put_guest_u16(vcpu, __LC_SUBCHANNEL_ID,
- inti->io.subchannel_id);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u16(vcpu, __LC_SUBCHANNEL_NR,
- inti->io.subchannel_nr);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u32(vcpu, __LC_IO_INT_PARM,
- inti->io.io_int_parm);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = put_guest_u32(vcpu, __LC_IO_INT_WORD,
- inti->io.io_int_word);
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_to_guest(vcpu, __LC_IO_OLD_PSW,
- &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
-
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- __LC_IO_NEW_PSW, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
+ rc = put_guest_u16(vcpu, __LC_SUBCHANNEL_ID,
+ inti->io.subchannel_id);
+ rc |= put_guest_u16(vcpu, __LC_SUBCHANNEL_NR,
+ inti->io.subchannel_nr);
+ rc |= put_guest_u32(vcpu, __LC_IO_INT_PARM,
+ inti->io.io_int_parm);
+ rc |= put_guest_u32(vcpu, __LC_IO_INT_WORD,
+ inti->io.io_int_word);
+ rc |= copy_to_guest(vcpu, __LC_IO_OLD_PSW,
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ __LC_IO_NEW_PSW, sizeof(psw_t));
break;
}
default:
BUG();
}
- if (exception) {
+ if (rc) {
printk("kvm: The guest lowcore is not mapped during interrupt "
- "delivery, killing userspace\n");
+ "delivery, killing userspace\n");
do_exit(SIGKILL);
}
}
static int __try_deliver_ckc_interrupt(struct kvm_vcpu *vcpu)
{
- int rc, exception = 0;
+ int rc;
if (psw_extint_disabled(vcpu))
return 0;
if (!(vcpu->arch.sie_block->gcr[0] & 0x800ul))
return 0;
- rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1004);
- if (rc == -EFAULT)
- exception = 1;
- rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
- &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
- rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
- __LC_EXT_NEW_PSW, sizeof(psw_t));
- if (rc == -EFAULT)
- exception = 1;
- if (exception) {
+ rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1004);
+ rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
+ &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+ rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+ __LC_EXT_NEW_PSW, sizeof(psw_t));
+ if (rc) {
printk("kvm: The guest lowcore is not mapped during interrupt "
"delivery, killing userspace\n");
do_exit(SIGKILL);